(GPS: N37° 55.660 W119° 02.760)
Let me try to explain this by just rehashing what I have read since I am not a geologist or scientist of any sort. Magma rose up and reached the cool water which created an explosion that produced the crater you see above and below. Afterwords, more magma (lava when it reaches the surface) came up in the middle part of the crater creating the inner dome part you see.
I headed back and went to the "plug trail" which takes you inside the intermost dome of the crater. You come out and in an "otherworldly" type of area:
There are lots of these spires around... Tons of obsidian and pumice around...
This area reminds me of a fantasy movie or something you might see in the Lord of the Rings books/movies.
It is one of those areas that I am not sure if videos and pictures do it justice, but it is out of this world! If I were to change the backgrounds in these pictures it might look like I was on another planet. A few other links for further information: